E10 gas will kill milleage.
Gallon for gallon, pure ethanol contains one-third less energy than gasoline, and the ethanol industry acknowledges that E10 reduces mileage by about 2 percent.
Some drivers think the change is notably greater. Chuck Mai, a vice president of AAA Oklahoma, reported that his organization has been getting calls from members blaming E10 for mileage drops of 8 to 20 percent.
In chat rooms at Edmunds.com and elsewhere, plenty of people are blaming ethanol for substantial mileage drops.
